Finasteride
Propecia, Proscar
Forms: Tablets for hair loss and, at a higher strength, for prostate enlargement; topical forms are approved in some countries.
A 5α-reductase inhibitor that blocks the conversion of testosterone into the more potent androgen DHT. Prescription treatment for male-pattern hair loss and an enlarged prostate.
Legal status: Prescription medicine in most countries; not on the WADA Prohibited List.
What it gives
What people use it for and what the sources report. Strength is a general category from the literature: mild, clear or strong.
Purpose
Approved for male-pattern hair loss and benign prostate enlargement. In sport, used to limit hair loss and prostate growth during testosterone use. Prescription only, under a doctor: it doesn't help with every steroid and can backfire with nandrolone.
What people seek and what studies show
It lowers blood DHT by about 70% and scalp DHT by almost two-thirds. In large trials in men with male-pattern hair loss it slowed loss and increased hair counts over five years, while men on placebo kept losing hair. In older men on testosterone replacement it curbed prostate growth and the PSA rise without blunting gains in muscle, strength or bone. It has not been studied at sport doses of steroids.
Effects
Evidence: Approved medicine — studied in people for its medical use
Sought effects by goal (as reported)
Possible side effects
Possible does not mean certain: whether they appear depends on dose, duration, individual response and monitoring. Below — what to watch for and how to notice it early.
3 possible side effects
level · how often it is reportedWhat the levels mean
Level: general category from the literature, not your personal risk
How often
- common
- reported often
- possible
- reported in some people
- rare
- reported occasionally
How to lower the risks
For 3 of 3 possible side effects there are specific ways to lower the chance: everyday measures, supplements and options a doctor may consider. No measure removes a risk completely.
Keep routine and social contact; talk to a specialist if low mood persists.
How each option helps (2)
- Working with a doctor — Mood problems, especially after stopping steroids, are treatable; a doctor can refer you to mental-health care.
- Sleep hygiene — Good sleep supports mood, especially in the low-hormone phase after stopping steroids.
Find the cause by tests (estradiol, prolactin, testosterone) rather than guessing.
How each option helps (1)
- Working with a doctor — Finds the cause of low libido or erectile problems instead of masking it.
React early: see a doctor at the first lump, check estradiol and prolactin.
How each option helps (1)
- Working with a doctor — Early assessment of breast-tissue growth allows treatment before the change becomes permanent.
Check-ups and blood tests
Which tests and check-ups to do and when. This is a guide — agree the exact schedule with your doctor.
Which doctors can help
Get medical help at once if
- Thoughts of suicide or self-harm — contact emergency services or a crisis line right now.
- A painful lump under the nipple or nipple discharge — see a doctor early, while it can still regress; a hard, painless or fixed lump, skin dimpling or bloody discharge — see a doctor promptly.
In an emergency, call your local emergency number.
For women
Contraindicated in women who are or may become pregnant: it can disrupt genital development of a male fetus, so they must not handle crushed or broken tablets.
Myth & fact
“Finasteride prevents hair loss whatever steroid you use.”
It only blocks testosterone→DHT. DHT-derived steroids bypass it, and with nandrolone it can backfire: the weaker dihydronandrolone isn't formed, so stronger nandrolone acts on the scalp.
Combinations
In skin and scalp, 5α-reductase turns nandrolone into a much weaker androgen. Finasteride or dutasteride block that step, so more active nandrolone stays there: they do not protect against its hair loss and may make androgenic effects stronger.
NandroloneDutasterideSame enzyme, same goal: together they add no meaningful benefit, while sexual side effects and mood changes can add up.
DutasterideSources
Possible side effects by body system, combinations, how to lower the risks and which tests to do — free.
Open the stack check